This invention refers to a programmable cylinder lock which comprises devices intended to allow, through a change operation, adapting the lock to a key different from a key to which the lock was formerly adapted.
Through the present description, the word "lock" is intended to designate, in addition to the usual locks for doors or leaves, also any kind of special locks, such as padlocks and others.
Various embodiments of cylinder locks suitable to behave in the above stated manner are known, and among them there is, in particular, the lock according to the U.S. Pat. No. 4,712,399. In the following, through the present description reference is made to programming mechanisms substantially conforming the mechanisms of said United States Patent, but it should be realized that the present invention is not limited to the use of such mechanisms, and it may also be applied to cylinder locks using different programming mechanisms.
There are also known masterizable locks which, thanks to the use of locking pins subdivided in two or more sections, may be operated both by an individual key singularly adapted to a specific lock, and by one or more other keys, called master keys, which may also operate other locks, each one of them being also operable by an individual key. This allows to establish within a group of locks a hierarchy on two or more levels, whereby each lock may be operated by its own key, which cannot operate the other locks of the group, as well as by a master key, which is capable of operating all the locks of the group, and possibly also by one or more other master keys of lower level, each one adapted to operate all the locks of a specific sub-group, but not the locks of the other sub-groups being part of the whole lock group taken in consideration.
However, in the known embodiments, the programmable cylinder locks cannot be provided with master keys, whereas the cylinder locks provided with master keys are not suitable for being programmed.